Atomic structure and periodic table

Question 1

What are elements?

Answer 1

An element is a substance that cannot be broken down into any other substance.

Question 2

What are compounds?

Answer 2

Compounds are chemical substances made up of two or more elements that are chemically bound together.

Question 3

What is a mixture?

Answer 3

A mixture is made when two or more substances are combined, but they are not combined chemically

Question 4

What are separating techniques for mixtures?

Answer 4

Filtration (filter paper etc.)
Distillation (evaporating water and leaving solid)
Evaporation (evaporating water then leaving to cool to form crystals)

Question 5

What is the difference between the plum-pudding model and the nuclear model?

Answer 5

Plum-pudding model = electrons in positively charged ‘soup’

Nuclear model = electrons orbit nucleus

Question 6

What is the relative charge of protons neutrons and electrons?

Answer 6

Proton = +1
Neutron = 0
Electron = -1

Question 7

What is the relative mass of protons, neutrons and electrons?

Answer 7

Proton = 1
Neutron = 1
Electron = 0

Question 8

Which is the mass number and which is the atomic number?
23
NA
11

Answer 8

Mass number (top) = 23
Atomic number (bottom) = 11

Question 9

How do you find the number of protons, neutrons and electrons from the atomic and mass number.

Answer 9

Protons = atomic number
Electrons = atomic number 
Neutrons = mass number - atomic number

Question 10

What are isotopes?

Answer 10

Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.

Question 11

What is relative atomic mass?

Answer 11

The relative atomic mass of an element is defined as the weight in grams of the number of atoms of the element contained in 12.00 g of carbon-12.

Question 12

Why do isotopes affect the relative atomic mass?

Answer 12

The relative atomic mass of an element is a weighted average of the masses of the atoms of the isotopes - because if there is much more of one isotope then that will influence the average mass much more than the less abundant isotope will.

Question 13

How do you find the relative atomic mass of an element given the abundance of its isotopes?

Answer 13

                       (percentage 1 + percentage 2)

Question 14

How are elements in the periodic table arranged?

Answer 14

The chemical elements are arranged in order of increasing atomic number.

Question 15

How are elements with similar properties placed in the periodic table?

Answer 15

Elements with similar properties are placed in vertical columns, called groups. elements in the same group have the same number of electrons in their outer shell.

Question 16

Describe the early attempts to classify elements.

Answer 16

Early chemists attempted to classify the elements according to their relative atomic mass.

Question 17

Explain the creation and attributes of Mendeleev’s periodic table.

Answer 17

Mendeleev arranged the elements in order of increasing relative atomic mass. He then arranged the elements by putting those with similar properties below each other into groups.

Question 18

Describe noble gases (group 0) and explain their lack of reactivity.

Answer 18

When elements react, their atoms complete their outer shells by losing, gaining, or sharing electrons . The atoms of noble gases already have complete outer shells, so they have no tendency to lose, gain, or share electrons.

Question 19

What are the properties of noble gases?

Answer 19

Low boiling points.

Boiling point increases going down the group.

Question 20

Describe the reactivity and properties of alkali metals (group 1).

Answer 20

Reactivity increases down the group. This is because the outer electron in each atom is further away from the nucleus as you go down the group.

Question 21

Describe the properties of halogens (group 7).

Answer 21

The halogens have low melting points and low boiling points.
The halogens become darker as you go down the group.
Gas —> liquid —> solid as you go down the group
Get less reactive as you go down the group.

Question 22

Describe the reactions of halogens with metals and non-metals.

Answer 22

Halogen + metal —> salt

Halogen + hydrogen —> compound